I get that, I’ve got it on my iPhone as I need to test out my own apps, but haven’t done so on tvOS yet, and most of the warnings and horror stories seem to be limited to iOS and iPad OS which is why I wondered what some major issues channels related are to tvOS.

Keep in mind that new tvOS beta releases and/or new Channels versions could regress tvOS beta compatibility at any point. And it's not possible to downgrade tvOS without erasing your device and starting over (a backup made on the tvOS beta cannot be restored onto the previous, stable version of tvOS).

That being said, so far on the iOS 13 beta, Channels has been very stable for me. I'd imagine tvOS is similarly livable. But again, this could change at any moment before the final release.